A 35-year-old woman with a 3-year history of progressive hearing loss presents for evaluation. Pure tone audiometry shows bilateral low-frequency sensorineural hearing loss with a characteristic dip at 2 kHz (Carhart notch). High-resolution CT temporal bone reveals demineralisation around the oval window and cochlear involvement. She is counselled about surgical options. Which of the following is the gold standard surgical treatment for her condition?

Explanation

## Clinical Context This patient has **otosclerosis with mixed hearing loss** (conductive + sensorineural components): - Carhart notch at 2 kHz is pathognomonic for otosclerosis - Bilateral low-frequency sensorineural loss indicates cochlear involvement - CT findings confirm stapes footplate fixation and otic capsule demineralisation ## Carhart Notch: A High-Yield Sign **Mnemonic:** **CARHART = Conductive hearing loss + Abnormal bone conduction Remodelling + Threshold At 2 kHz + Hearing loss + Audiometric Reduction + Ringing tinnitus** **Key Point:** A characteristic **bone conduction dip at 2 kHz** (with air conduction relatively preserved at that frequency) is virtually diagnostic of otosclerosis. It reflects abnormal ossicular resonance from stapes fixation. ## Surgical Management ### Stapedectomy: Gold Standard **High-Yield:** Stapedectomy (or stapedotomy) is the definitive surgical treatment for conductive/mixed hearing loss in otosclerosis. **Procedure:** 1. **Removal or mobilisation of fixed stapes footplate** 2. **Insertion of ossicular replacement prosthesis (ORP)** — typically: - Partial ossicular replacement prosthesis (PORP): connects incus to oval window - Total ossicular replacement prosthesis (TORP): connects malleus/tympanum to oval window 3. Restoration of ossicular chain continuity **Outcomes:** - **>90% success rate** in closing air–bone gap - Hearing improvement of 20–30 dB in most cases - Tinnitus relief in 60–70% of patients ### Indications for Surgery | Criterion | Details | |-----------|----------| | **Conductive component** | Air–bone gap >20 dB | | **Bone conduction threshold** | Better than 45 dB (predicts good surgical outcome) | | **Bilateral disease** | Often both ears affected; surgery staged | | **Patient motivation** | Hearing aid intolerance, occupational need | | **Age** | Any age if symptomatic; earlier if progressive | ## Why Other Options Fail **Clinical Pearl:** Cochlear implantation is reserved for **profound bilateral sensorineural hearing loss** (bone conduction >45 dB) or when stapedectomy has failed. In this case, the conductive component is still addressable surgically. **Tip:** Myringoplasty and mastoidectomy address middle ear infection/perforation, not stapes fixation. Ossiculoplasty alone cannot overcome stapes fixation. ## Complications of Stapedectomy - Perilymphatic fistula (0.5–1%) - Sensorineural hearing loss (1–2%) - Tinnitus persistence or worsening (5–10%) - Vertigo (transient in most; persistent in <1%) - Ossicular prosthesis extrusion (rare) [cite:Scott-Brown's Otolaryngology 8e Ch 3.7; Cummings Otolaryngology 7e Ch 135]